1. Field of the Invention
The present invention relates to a portable electronic device including a cellular phone, a Personal Digital Assistant (PDA), a Hand Held Phone (HHP), and a communication device. More particularly, the present invention relates to a portable electronic device having a sliding housing adapted to slide in multiple directions so that it incorporates a key input function.
2. Description of the Related Art
Generally, the term “portable terminal” refers to a device used to provide wireless communication between users or between users and service providers via mobile communication base stations, for example. Various types of service content, including voice communication, short message transmissions, mobile banking, TV viewing, online games, and Videos on Demand (VODs), are provided to users via a portable terminal.
Furthermore, the term “terminal” commonly refers to a video player, a camera, a portable electronic device, a Personal Computer (PC), or a Portable DVD Player (PDP). Conventional portable electronic devices include HHPs, CT-2 cellular phones, digital phones, Personal Communication Service (PCS) phones, and Personal Data Assistants (PDAs).
Portable terminals are classified into bar-type terminals, flip-type terminals, and folder-type terminals according to their appearance. Bar-type terminals have a single bar-shaped housing. Flip-type terminals have a bar-shaped housing and a flip or a cover rotatably connected to the housing by a hinge device. Folder-type terminals have a single bar-shaped housing and a folder rotatably connected to the housing by a hinge device to be folded/unfolded. Conventional portable terminals, as mentioned above, are necessarily equipped with an antenna device, a data input/output device, and a data transmission/reception device. Key buttons are commonly used as the data input device so that data can be input based on finger pressing operations. A touch pad or a touch screen may also be used.
Portable electronic devices also incorporate a function for sending/receiving text messages by using key buttons.
Key buttons for data input basically include a number of key arrays. Particularly, the key buttons include a SEND key for initiating communication, a CANCEL key, a CLEAR key, numeric keys, character keys, an END key, function keys, and a POWER key.
In addition, the key buttons include a keypad, direction keys, and navigation keys on the front surface of the terminal, as well as a number of side keys acting as auxiliary function keys of the key pads.
The key input device for portable electronic devices also includes navigation keys for movement in the upward, downward, leftward, and rightward directions. By using the appropriate navigation key, the direction of movement of the activated cursor by the user can be determined and the cursor moved in that direction.
However, conventional navigation keys have a problem in that they include at least four keys to implement the necessary operations. Requiring four keys makes it difficult to render portable electronic devices compact.
Furthermore, even if realized, as the portable devices are reduced in size, the direction keys become very small. Such a small size makes it difficult to operate the keys correctly, thus causing an inconvenience for the user. The small size in addition to the fact that at least four keys must be provided only worsens the problem.